JP2010067863A - Light emitting device, and light emitting module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress variations in the color of outputted light, and to increase the flexibility in the arrangement of a light emitting element, in a light emitting device which converts the wavelength of light outputted from the light emitting element using a phosphor. <P>SOLUTION: The light emitting device 60 includes: a metal lead section provided so that it is exposed to a bottom face 70 of a recess 61a in a resin vessel 61; a first semiconductor light emitting element 64a, a second semiconductor light emitting element 64b, and a third semiconductor light emitting element 64c mounted to the metal lead section on the bottom face 70 of the recess 61a; and a sealing resin 65 for covering the recess 61a. Here, the resin vessel 61 is composed of a white resin, and the metal lead section is composed by forming a silver-plated layer having glossiness set in a range of not less than 0.3 to not more than 1.0 on a metal plate with a copper alloy, or the like, as a base. Also, the sealing resin 65 contains phosphor powder 65a containing two kinds of phosphors, and a transparent resin 65b where the phosphor powder 65a has been dispersed, and an emission surface 65c of the sealing resin 65 is formed in a recess. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting device and a light emitting module using a light emitting element.

  2. Description of the Related Art In recent years, white LED (Light Emitting Diode) has been adopted as a backlight of a liquid crystal display of a mobile phone, and the production amount of white LEDs has been dramatically increased. Here, the white LED package is a light emitting device including a semiconductor light emitting element (LED), and is disposed so as to expose the lead frame inside the concave portion of the white resin case having the concave portion, for example. A semiconductor light emitting element is attached to the lead frame exposed to the inside, and these are electrically connected, and a sealing resin containing a phosphor is formed in the concave portion so as to cover the semiconductor light emitting element. In the future, it is expected that the use of white LEDs for the backlight of liquid crystal displays will be widespread even in applications other than mobile phones. In addition, as the amount of liquid crystal display used as a backlight increases, adoption in other lighting fields is also being studied. In the future, it seems to be certain that white LEDs will be used for the backlight of liquid crystal displays in applications other than mobile phones. As the amount of liquid crystal displays used as backlights increases, adoption in other lighting fields is also being considered.

  When a white LED is used as a backlight of a liquid crystal display, in order to obtain a specified luminance with a power as small as possible on a large screen, a highly efficient package equipped with the white LED is extremely demanded. Furthermore, there are strict standards for color variations across the display surface of a liquid crystal display. For example, if it is defined as the chromaticity range of the CIE Yxy color system, it is required to suppress variations of about ± 0.008 in each of x and y. In order to keep the color variation on the entire display surface of the display within the above-mentioned range, the package needs to be within the range.

  If you find a package that deviates from the required range by measuring it with a handler tester, you must remove the package. Thus, the cost of the package will increase by that amount unless all packages are within the required chromaticity range. In other words, in order to popularize lighting using white LEDs (including backlights), it is necessary to reduce the cost of the white LED package. To that end, the cause of the brightness reduction is eliminated as much as possible in the package manufacturing process. In addition, it is required to reduce the color variation as much as possible.

  By the way, in the white LED package, not all the light generated in the semiconductor light emitting element is effectively used, and there are quite a portion that is confined inside the package and cannot come out. Since the sealing resin generally has a refractive index of 1.4 to 1.5 and air is 1, light incident at a certain incident angle or less is reflected and returned to the original due to the difference in refractive index. Assuming that there is a light emitter (for example, a semiconductor light-emitting element) at the center of the spherical surface, all light output from the light emitter is incident at a right angle to the boundary surface and is not reflected, and light extraction efficiency Is said to be the highest. Thus, many light emitting devices (packages) have been proposed in which a hemispherical lens is formed and a light emitter is arranged at the center thereof.

  However, when a prototype of a light-emitting device is actually manufactured, such a structure does not provide sufficient luminous efficiency, chromaticity varies greatly from direction to direction, and chromaticity variation between packages is practical. I couldn't do anything to endure. There are two types of color variations, and there are cases where the chromaticity varies from package to package and chromaticity varies depending on the direction (position) of one package. Thus, various techniques have been proposed for improving the light extraction efficiency to the limit and suppressing variations in these two types of colors (see Patent Documents 1 to 4).

  Furthermore, if the chromaticity of the light output from the package changes with time, it deviates from the standard, so it is necessary to suppress the change in luminance and chromaticity with time as much as possible. Therefore, sufficient study is required for the resin material and the sealing resin of the resin container in which the reflector is formed in order to suppress discoloration of the plating surface of the lead frame.

  In Patent Document 1 and Patent Document 2, there is the following description in order to prevent chromaticity from being different depending on directions in one package. That is, it is an essential requirement that the thickness of the resin layer containing the phosphor existing from the light emitting element to the light extraction surface of the light emitting device is constant. In order to achieve this, the package is made into a special shape or the sealing resin is divided into two layers, and the phosphor-containing layer is used to cover the light emitting element with a uniform thickness, or to the outer periphery of the package with a uniform thickness. It is necessary to apply a phosphor-containing sealing resin.

  Therefore, Patent Document 3 proposes the following method mainly for the purpose of preventing variation in chromaticity depending on the direction. That is, when the sealing resin is injected into the white package container, the phosphor partially sinks, and the distance through which the sealing resin light passes from the light emitting semiconductor light emitting element cannot be made constant. As a variation, it has been proposed that the phosphor-containing layer is formed by another method such as electrophoresis in which particles do not settle, and the thickness of the phosphor-containing layer is made uniform.

  On the other hand, Patent Document 4 proposes a method different from the above to prevent the emission color from varying depending on the direction of one package. That is, by uniformly dispersing the phosphor in the sealing resin, it is possible to prevent the chromaticity from being varied depending on the direction in one package. However, as described in Patent Documents 1, 2, and 3, in a package in which the distance from the light emitted from the light emitting element to the outside through the sealing resin is different, the phosphor is only uniformly dispersed in the sealing resin. However, of the two variation factors, there is an effect in suppressing variation in chromaticity between packages, but it is not possible to suppress variation in chromaticity depending on the direction in one package.

Even if the phosphor is uniformly dispersed in the sealing resin, if the thickness of the phosphor-containing sealing resin layer covering one light emitting element varies, the emission color varies depending on the direction in one package. Furthermore, if the thickness of the layer containing the phosphor differs for each package, the chromaticity varies for each package. Regarding the variation in chromaticity for each package, there is no clear description on how to prevent it, but in practice it is a precondition that the thickness of the phosphor-containing sealing resin layer covering the light emitting element should be the same as much as possible. It is thought that.
US Pat. No. 6,576,930 US Pat. No. 7,126,162 JP 2003-110153 A JP 2005-277441 A

  Illumination using light emitting elements such as LEDs has been developed mainly as a demand for backlights used in liquid crystal displays. However, at present, small displays for cellular phones are mainly used, and are hardly adopted for large area liquid crystal displays such as monitors for personal computers and large TVs. This is because, as described above, the luminance is not sufficient, the stability against color variations, and the stability against changes with time in luminance and color constellation are not sufficiently ensured.

  In the case of a liquid crystal display such as a mobile phone, there is no practical problem even if the color reproduction range is about 70% in terms of NTSC ratio. Therefore, it is common to develop a white color with a combination of a yellow phosphor and a blue LED. On the other hand, in the case of a large-sized liquid crystal television, a color reproduction range of 82% or more is required at least as compared with NTSC. In order to achieve this, it is difficult to use a single yellow phosphor, and it is necessary to use a mixture of a green phosphor that emits green light with blue light and a red phosphor that emits red light. When two types of phosphors are used in this way, unless the phosphors are uniformly dispersed, the chromaticity varies among the light emitting devices and the chromaticity varies depending on the direction within the same light emitting device. Will become more and more serious.

  However, since the green phosphor and the red phosphor generally have different densities and particle size distributions, there is a difference in sedimentation speed, and the chromaticity of the emission color changes. The variation in chromaticity depending on the direction of one light emitting device and the variation in chromaticity for each light emitting device are minimized, and both chromaticity x and y, which are standards required for a backlight of a liquid crystal display device, are ± 0.008. Manufacturing technology is required to put 95% or more in the inside.

  Further, in a package configured by combining a semiconductor light emitting element and a phosphor, chromaticity of output light may vary depending on a position where the semiconductor light emitting element is mounted. For example, the emission color of the semiconductor light emitting element is stronger than the emission color of the phosphor on the side closer to the semiconductor light emitting element, and the emission color of the phosphor is stronger because the emission color of the semiconductor light emitting element is weaker on the side farther from the semiconductor light emitting element. Tend to be.

  The present invention provides a light-emitting device that converts the wavelength of light output from a light-emitting element using a phosphor, and increases the degree of freedom in arranging the light-emitting elements while suppressing variations in the color of the output light. Objective.

  For such a purpose, a light emitting device to which the present invention is applied includes a resin container provided with a recess including a bottom surface and a wall surface rising from the peripheral edge of the bottom surface, a metal conductor, and a surface formed on the surface of the metal conductor. And a silver plating layer having a glossiness of 3 or more and 1.0 or less, and the conductor portion disposed in a state exposed on the bottom surface of the recess of the resin container is different from the center position of the bottom surface of the recess. A light emitting element that is attached to a position and is electrically connected to a conductor, a transparent resin that is transparent to the light emitting wavelength of the light emitting element, and dispersed in the transparent resin to convert the light emitting wavelength of the light emitting element into longer wavelength light And a sealing resin for sealing the light emitting element in the recess.

In such a light emitting device, the conductor portion reflects light from the light emitting element by a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. can do.
The resin container may be whitened using a white pigment.
Furthermore, the glossiness of the silver plating layer in a conductor part can be characterized by being 0.5 or more and 0.7 or less.
Furthermore, the light emitting element outputs blue light, and the phosphor is a first phosphor that converts blue light into green light and outputs it, and a second phosphor that converts blue light into red light and outputs it. It can be characterized by including.
Further, the transparent resin may be composed of a silicon resin.
The sealing resin has an emission surface that emits the light output from the light emitting element to the outside, and the emission surface has a concave shape that is recessed from the boundary side to the center side with the resin container. The depression amount of the exit surface is set in a range of 20 μm or more and 100 μm or less.

  From another point of view, the light emitting device to which the present invention is applied includes a resin container having a recess, a metal conductor, and a glossiness of 0.3 or more and 1.0 or less formed on the surface of the metal conductor. A conductor part formed in a state exposed to the inside of the recess of the resin container, a plurality of light emitting elements provided inside the recess and electrically connected to the conductor part, A transparent resin transparent to the emission wavelengths of a plurality of light emitting elements, and a phosphor dispersed in the transparent resin that converts the light emission wavelength of the light emitting elements into light having a longer wavelength, and sealing the plurality of light emitting elements in the recesses Sealing resin.

In such a light emitting device, the conductor portion reflects light from the light emitting element by a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. can do.
Further, the resin container may be formed of a resin containing titania fine particles.
Furthermore, the glossiness of the silver plating layer in a conductor part can be characterized by being 0.5 or more and 0.7 or less.
Furthermore, the light reflectance of the resin container and the silver plating layer of the conductor in the visible region may be 85% or more and 98% or less.
And the area of the conductor part exposed to the bottom face of a recessed part can be set to the half or more of the total area of a bottom face, It can be characterized by the above-mentioned.

  Further, from another viewpoint, the light emitting module to which the present invention is applied includes a substrate and a plurality of light emitting devices attached to the substrate, and the light emitting device includes a bottom surface and a wall surface rising from a peripheral edge of the bottom surface. A resin container having a recess, a metal conductor, and a silver plating layer having a glossiness of 0.3 to 1.0 formed on the surface of the metal conductor and exposed to the bottom surface of the recess of the resin container A light emitting element that is attached to a position different from the center position of the bottom surface, and is transparent to the light emission wavelength of the light emitting element. It includes a transparent resin and a phosphor that is dispersed in the transparent resin and converts the emission wavelength of the light emitting element into light having a longer wavelength, and has a sealing resin that seals the light emitting element in the recess.

In such a light emitting module, the conductor portion of the light emitting device reflects light from the light emitting element by a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. Can be characterized.
In addition, the resin container of the light emitting device may be whitened using a white pigment.
Furthermore, the glossiness of the silver plating layer in the conductor part of the light emitting device may be 0.5 or more and 0.7 or less.

  According to the present invention, in a light-emitting device that performs wavelength conversion of light output from a light-emitting element using a phosphor, the degree of freedom in arrangement of the light-emitting elements is increased while suppressing variations in the color of the output light. be able to.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
<Embodiment 1>
FIG. 1 is a diagram showing an overall configuration of a liquid crystal display device to which the present embodiment is applied. The liquid crystal display device includes a liquid crystal display module 50 and a backlight device 10 provided on the back side (lower side in FIG. 1) of the liquid crystal display module 50.

  The backlight device 10 includes a backlight frame 11 and a plurality of light emitting modules 12 in which light emitting devices are respectively arranged and accommodated in the backlight frame 11. In addition, the backlight device 10 is a laminated body of optical films, and has a diffusion plate 13 that is a plate (or film) that scatters and diffuses light in order to make the entire surface uniform brightness, and a light collecting effect forward. Prism sheets 14 and 15 are provided. Further, a diffusion / reflection type brightness enhancement film 16 for improving the brightness is provided as necessary.

  On the other hand, the liquid crystal display module 50 is laminated on each glass substrate of the liquid crystal panel 51, which is configured by sandwiching liquid crystal between two glass substrates, and restricts vibration of light waves in a certain direction. Polarizing plates 52 and 53. Furthermore, peripheral members such as a driving LSI (not shown) are also mounted on the liquid crystal display device.

  The liquid crystal panel 51 includes various components not shown. For example, two glass substrates are provided with a display electrode (not shown), an active element such as a thin film transistor (TFT), a liquid crystal, a spacer, a sealant, an alignment film, a common electrode, a protective film, a color filter, and the like. .

  FIG. 2 is a diagram for explaining the structure of the backlight device 10. Here, FIG. 2A is a top view of the backlight frame 11 to which the light emitting module 12 is mounted as seen from the liquid crystal display module 50 side shown in FIG. 1, and FIG. 2B is a plan view of FIG. It is IIB-IIB sectional drawing of. In the present embodiment, a direct type backlight structure in which a light source is placed directly under the back surface of the liquid crystal display module 50 is employed. In this backlight structure, the light emitting devices 60 having the light emitting elements are arranged substantially evenly with respect to the entire back surface of the liquid crystal display module 50. The light emitting device 60 used in the present embodiment is generally called an LED package.

  The backlight frame 11 forms a housing structure made of, for example, aluminum, magnesium, iron, or a metal alloy containing them. And the polyester film etc. which have the performance of white high reflection, for example are affixed inside the housing | casing structure, and it functions also as a reflector. The casing structure includes a back surface portion 11a provided corresponding to the size of the liquid crystal display module 50 and side surface portions 11b surrounding the four corners of the back surface portion 11a. And the heat-radiation sheet 18 can be provided on this back surface part 11a.

  In the example shown in FIG. 2, a plurality of light emitting modules 12 (eight in this example) are provided. Each light emitting module 12 is fixed to the backlight frame 11 via a heat dissipating sheet 18 by a plurality of screws 17 (two for each light emitting module 12 in this example).

  The light emitting module 12 includes a wiring board 20 as an example of a board and a plurality (28 in this example) of light emitting devices 60 mounted on the wiring board 20. In addition, each light-emitting device 60 is equipped with the structure mentioned later, and each outputs white light.

  FIG. 3 is a diagram for explaining the configuration of the light emitting device 60 used in the present embodiment. Here, FIG. 3A shows a top view of the light emitting device 60, and FIG. 3B shows a IIIB-IIIB sectional view of FIG.

  The light emitting device 60 includes a resin container 61 having a recess 61a formed on the upper side, a first anode lead part 62a, a second anode lead part 62b, and a third anode, each of which is a lead frame integrated with the resin container 61. Lead portion 62c and cathode lead portion 63, first semiconductor light emitting element 64a, second semiconductor light emitting element 64b and third semiconductor light emitting element 64c attached to bottom surface 70 of recess 61a, and recess 61a are provided. The sealing resin 65 is provided. In FIG. 3A, the description of the sealing resin 65 is omitted.

  The resin container 61 is a thermoplastic resin in which a white pigment is contained in a metal lead portion including a first anode lead portion 62a, a second anode lead portion 62b, a third anode lead portion 62c, and a cathode lead portion 63. (Hereinafter referred to as white resin) is formed by injection molding.

  The white resin constituting the resin container 61 has the white pigment content, particle size, and the like adjusted such that the visible light reflectance is 85% or more and 98% or less. In other words, the visible light absorption rate of the resin container 61 is less than 15%. As the white pigment, titania (titanium oxide) fine particles are preferably used. Since titania has a higher refractive index and a lower light absorption rate than other white pigments, it can be suitably used for the resin container 61 of the present embodiment. Other white pigments, such as aluminum oxide, are not preferable as compared with titania because the brightness is greatly reduced as compared with titania. However, since titania has a photocatalytic action, the resin may be altered. Therefore, it is preferable to perform a surface treatment on titania with aluminum hydroxide or the like. If this surface treatment is not sufficient, the resin constituting the resin container 61 is altered and absorbs a specific wavelength, so that the chromaticity coordinate may change over time. Therefore, the selection of titania as a white pigment and the amount of addition are extremely important. In order to improve the light reflectivity of the resin container 61, it is better to increase the amount of titania added. However, in order to make the shape of the resin container 61 by injection molding or the like, there is a face that the fluidity is lowered. There is an upper limit to the amount added.

  In addition, since there are a plurality of processes that require temperature such as solder reflow in the manufacturing process, a material that sufficiently considers heat resistance is selected for the white resin. PPA (polyphthalamide) is most commonly used as the base resin, but may be a liquid crystal polymer, an epoxy resin, polystyrene, or the like.

  The recess 61 a provided in the resin container 61 includes a bottom surface 70 having a circular shape and a wall surface 80 that rises from the periphery of the bottom surface 70 toward the upper side of the resin container 61. Here, the bottom surface 70 includes the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, the cathode lead portion 63, and the first anode lead portion 62a exposed in the recess 61a. And the white resin of the resin container 61 exposed in the gap between the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63. However, more than half of the bottom surface 70 is occupied by the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63. On the other hand, the wall surface 80 is made of a white resin constituting the resin container 61. The shape of the bottom surface 70 may be any of a circle, a rectangle, an ellipse, and a polygon. Moreover, the shape of the wall surface 80 may be any of a circle, a rectangle, an ellipse, and a polygon, may be the same as the shape of the bottom surface, and may be different as in the present embodiment.

  The first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63, which are examples of the conductor portion, are partially sandwiched in the resin container 61. A terminal for applying a current to the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c. It has become. When surface mounting is assumed, as shown in FIG. 3, the first anode lead part 62a, the second anode lead part 62b, the third anode lead part 62c, and the cathode lead part 63 are respectively made of resin containers. It is desirable that the front end of the resin container 61 be disposed at the bottom of the resin container 61 by bending it to the back side.

  The first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63, that is, the lead frame, is a metal plate having a thickness of about 0.1 to 0.5 mm. In this case, a metal conductor such as a copper alloy is used as a base, and a silver plating layer is formed on the surface by silver plating. Therefore, the silver plating layers of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63 are exposed on the bottom surface 70 of the recess 61a. Become. The light reflectance of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63, that is, the light reflectance of the silver plating layer is 85% or more and 98% or less. It is preferable that Further, the glossiness of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63 is within a range of 0.3 or more and 1.0 or less. Preferably, it is in the range of 0.5 or more and 0.7 or less. Here, the glossiness is defined by JISZ8741 and is a value when the incident angle of incident light is 60 °.

In general, by examining the conditions of silver plating, the state of unevenness on the surface can be controlled. The silver plating on the lead frame is generally electrolytic plating with a cyan solution. In electroplating, once silver is deposited, it becomes a protrusion, and current tends to concentrate at the sharp point, so the periphery of the protrusion grows further. As a result, so-called dendritic precipitation is likely to occur. This tendency is particularly remarkable in silver electroplating. When silver electrolysis of the cyan solution is performed at a high film formation rate, so-called matte white plating is obtained. This shows a light reflection characteristic very close to Lambertian reflection, but instead the light absorption rate is relatively high, exceeding 10%. On the other hand, when a brightening agent such as Se is added during silver plating, dendrite growth is suppressed and smoothed, and a surface exhibiting behavior close to complete specular reflection can be obtained. In this case as well, if the brightener is added until a complete mirror surface is obtained, the additive remains on the deposited surface and the light absorption rate increases. The shape (glossiness) of the silver plating surface can be adjusted by varying the Ag ⁺ concentration, temperature, pH, cyanide concentration, addition of other cations and anions, current density, organic additives, etc. It can be adjusted appropriately.

  The first semiconductor light emitting element 64a is on the first anode lead 62a exposed at the bottom surface 70 of the recess 61a, and the second semiconductor light emitting element 64b is on the second anode lead 62b exposed at the bottom 70 of the recess 61a. The third semiconductor light emitting element 64c is bonded and fixed to the third anode lead portion 62c exposed on the bottom surface 70 of the recess 61a with a die bond agent made of silicon resin or epoxy resin.

  Here, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c have an n-type electrode and a p-type electrode, respectively. The p-type electrode of the first semiconductor light emitting element 64a is connected to the first anode lead 62a, the p-type electrode of the second semiconductor light emitting element 64b is connected to the second anode lead 62b, and the p-type electrode of the third semiconductor light emitting element 64c. The mold electrodes are respectively connected to the third anode lead part 62c via bonding wires. On the other hand, the n-type electrode provided in each of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c is connected to a common cathode lead portion 63. Therefore, in the light emitting device 60, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c are connected in parallel.

  Further, in the light emitting device 60, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c are arranged at positions shifted from the center C of the bottom surface 70 having a circular shape. Yes.

  The first semiconductor light emitting element 64a emits blue light having a main emission peak in a wavelength region of 430 nm or more and 500 nm or less, and is formed on the seed layer made of AlN formed on the sapphire substrate. And a laminated semiconductor layer mainly composed of GaN. The laminated semiconductor layer is configured by laminating a base layer, an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer in this order from the substrate side. The second semiconductor light emitting element 64b and the third semiconductor light emitting element 64c also have the same configuration as the first semiconductor light emitting element 64a, and output blue light.

  The sealing resin 65 absorbs light emitted from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c to emit two or more types of phosphors (hereinafter referred to as fluorescent light). 65a and a transparent resin 65b containing the phosphor powder 65a in a uniformly dispersed state. In this example, the phosphor powder 65a includes a green phosphor that emits green light by absorbing blue light emitted from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c, and the first phosphor. A red phosphor that absorbs blue light emitted from the semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c and emits red light. Note that the red phosphor is also excited by the light emitted by the green phosphor. Therefore, the movement of the chromaticity of the light output from the light emitting device 60 varies very complicatedly depending on the ratio of the green and red phosphors. For such adjustment of chromaticity, the emission wavelength of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c, the ratio of the green and red phosphors, and the fluorescence in the sealing resin 65 are used. The body concentration is related to the upper surface of the sealing resin 65, that is, the shape of the emission surface 65c from which light is emitted.

  In the light emitting device 60, the blue light emitted from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c, the green light emitted from the green phosphor contained in the phosphor powder 65a, Similarly, the three primary colors of blue, green, and red are aligned by the red light emitted from the red phosphor contained in the phosphor powder 65a. For this reason, white light is emitted from the emission surface 65 c of the sealing resin 65. When this white light is used as the backlight of the liquid crystal display device, the color reproduction range includes the wavelength and half width of the main emission peak of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c. It is determined by the wavelength and half-value width of the emission peak of the phosphor powder 65a.

The green phosphor as an example of the first phosphor suitably used for the phosphor powder 65a described above is preferably a silicate phosphor (BaSiO ₄ : Eu ²⁺ ), and an example of the second phosphor. The red phosphor is preferably a nitride phosphor (CaAlSiN ₃ : Eu ²⁺ ). These green phosphors and red phosphors have a relatively low true density of 3.5 g / cm ^{3 to} 4.7 g / cm ^3, and can produce a powder having an average particle diameter of about 10 μm on a mass average. Because.

Here, since the green phosphor (BaSiO ₄ : Eu ²⁺ ) has an excitation wavelength of 380 to 440 nm and an emission wavelength of 508 nm, the required characteristics for converting the blue light used in this embodiment into green light are obtained. On the other hand, both the excitation wavelength and the emission wavelength are too short. However, by replacing a part of Ba with other alkaline earth elements such as Sr, Ca, and Mg, the excitation wavelength and the emission wavelength can be moved to the longer wavelength side. In this embodiment, it is preferable to adjust the excitation wavelength to 455 nm and the emission wavelength of 528 nm, respectively.

The red phosphor (CaAlSiN ₃ : Eu ²⁺ ) has an excitation wavelength of 400 nm to 500 nm and an emission wavelength of 640 nm. The full width at half maximum of the peak wavelength varies depending on the purpose of use. For illumination purposes, it is preferable that the waveform of the peak wavelength is as broad as possible, but for the backlight application of the liquid crystal display device as in this embodiment, it is preferable that the waveform is as sharp as possible. In order to improve color rendering (the degree that looks the same as the color seen under sunlight) for lighting, it is necessary to have the same wavelength distribution as that of sunlight, and all wavelengths are included to the same extent. Is required. On the other hand, the color reproduction range when used for the backlight of a liquid crystal display device needs to be as wide as possible on the three chromaticity coordinates of blue, green, and red. That is, it is important that the color purity is as high as possible. For this purpose, it is preferable to make the wavelength distribution of the three primary colors as sharp as possible.

  On the other hand, as the transparent resin 65b that constitutes the sealing resin 65, various resins that are transparent in the visible region may be applied, but from the viewpoint of heat resistance, it is preferable to use a silicon resin.

Further, the sealing resin 65 is provided with an emission surface 65c that emits white light. In this example, as shown in FIG. 3B, an emission surface 65c is formed on the upper side of the resin container 61, that is, on the opening side of the recess 61a.
In the light emitting device 60, as shown in FIG. 3B, the central portion of the emission surface 65c is recessed from the upper surface of the resin container 61, and the amount d of the recess is in the range of −20 μm to −100 μm from the upper surface. Is set. The dent amount d is a difference between the height of the opening end of the resin container 61 and the minimum height of the emission surface 65c. Here, when the height of the opening end of the resin container 61 is set as a reference (0), the side approaching the bottom surface 70 is set to minus (−). Therefore, the range where the dent amount d is −20 μm to −100 μm from the upper surface means that the minimum height of the exit surface 65c is 20 μm to 100 μm above the upper surface when the height of the opening end of the resin container 61 is 0 μm. It means that it is located on the bottom surface 70 side.

  This dent amount d virtually sets the extended surface L of the opening end of the resin container 61, and the center point of the sealing resin 65 cured in the recessed portion 61a is A, and the distance between the point A and the extended surface L Ask. Actual measurement can be performed with a laser displacement meter (for example, ZSHLD2 manufactured by OMRON).

Now, the light emission operation of the light emitting device 60 shown in FIG. 3 will be described.
The first anode light-emitting element 64a, the second anode light-emitting element 64b, and the second anode light-emitting element 64b are formed by using the first anode lead part 62a, the second anode lead part 62b, and the third anode lead part 62c as a positive electrode and the cathode lead part 63 as a negative electrode. When a current is passed through each of the three semiconductor light emitting elements 64c, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c output blue light. The blue light output from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c travels in the sealing resin 65, and is emitted directly or after being reflected by the bottom surface 70 or the wall surface 80. The light is emitted from 65c to the outside. However, part of the light traveling toward the emission surface 65c is reflected by the emission surface 65c and travels through the sealing resin 65 again. During this time, in the sealing resin 65, part of the blue light is converted into green light and red light by the phosphor powder 65a, and the converted green light and red light are reflected directly or by the bottom surface 70 and the wall surface 80. Then, it is emitted to the outside from the emission surface 65c together with the blue light. Accordingly, white light including blue light, green light, and red light is emitted from the emission surface 65c.

  Like the light emitting device 60 of the present embodiment, the phosphor powder 65a is uniformly dispersed in the transparent resin 65b in the sealing resin 65, and the light reflectance of the sealing resin 65 is 85% or more and 98% or less. The behavior of light when stored in the recess 61a of the resin container 61 made of white resin is as follows. For example, of the light output from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c, the light incident on the white resin constituting the wall surface 80 and the bottom surface 70 is reflected and sealed. After returning to the stop resin 65 and making a complicated movement that goes back and forth as it enters the white resin, it finally passes through the sealing resin 65 and exits to the exit surface 65c. In this case, the reflection method and the light absorption rate of the silver plating layer provided on the bottom surface 70 have a great influence. In the present embodiment, the silver plating layer and the white resin constituting the bottom surface 70 and the wall surface 80 are provided with so-called Lambertian reflection type reflection characteristics, so that these are compared with the so-called specular reflection type reflection characteristics. Thus, the amount of light absorbed by the silver plating layer and the white resin on the bottom surface 70 and the wall surface 80 can be reduced. Therefore, the amount of light output from the light emitting device 60, that is, the brightness differs between the Lambertian reflection type reflection characteristic and the specular reflection type reflection characteristic. This is due to a difference, and if the light absorption rate is zero, there is no difference in output. In terms of sensation, the bottom surface 70 and the wall surface 80 constituting the recess 61a have a specular reflection type reflection characteristic from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c. It is considered that the output light can be guided to the emission surface 65c with a small number of reflections. However, in reality, because of the complicated behavior of light as described above, the light absorbed by the bottom surface 70 and the wall surface 80 is more improved when the bottom surface 70 and the wall surface 80 have Lambertian reflection characteristics. The amount can be reduced.

  Among these, the light directed toward the bottom surface 70 and the wall surface 80 is repeatedly reflected by the silver plating layer and the white resin constituting the bottom surface 70 and the wall surface 80, and finally exits to the emission surface 65c. On the other hand, the light traveling toward the emission surface 65 c is not related to the reflection on the bottom surface 70 or the wall surface 80, and a part thereof is scattered by the phosphor powder 65 a dispersed in the sealing resin 65. Then, after being reflected by the white resin constituting the wall surface 80 and again reflected by the silver plating layer on the bottom surface 70 and the white resin, the light exits to the emission surface 65c. In the process of scattering and reflection, light absorption occurs little by little. In order to extract light output from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c as effectively as possible, the number of times of scattering and reflecting the light is preferably as small as possible. However, from the viewpoint of suppressing variations in chromaticity depending on the position on the exit surface 65c as much as possible, it is better to repeat scattering and reflection thoroughly. As described above, the contradiction in that light output from the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c is extracted as effectively as possible and variation in chromaticity for each direction is eliminated. But in reality it is required.

  In response to such a demand, in the present embodiment, the resin container 61 is made of a white resin that absorbs little light, and the lead portion 62a for the first anode, the lead portion 62b for the second anode, which constitutes the lead frame, By forming a silver plating layer on the surfaces of the third anode lead part 62c and the cathode lead part 63, the light absorptance of visible light in the recess 61a is reduced. Specifically, the light absorptance in the visible region of the silver plating layer and the white resin constituting the bottom surface 70 and the wall surface 80 is in the range of more than 2% and less than 15%. In particular, in the present embodiment, the silver plating formed on the surfaces of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63 constituting the bottom surface 70. The glossiness of the light is made to be in the range of 0.3 to 1.0, and the wall surface 80 is made of white resin. Improves efficiency.

Next, a method for manufacturing the light emitting device 60 shown in FIG. 3 will be described with reference to FIG.
First, a white resin is injection molded into a lead frame in which the first anode lead 62a, the second anode lead 62b, the third anode lead 62c, and the cathode lead 63 are integrated, and the recess 61a is formed. A resin container 61 is formed. Next, the first semiconductor light emitting element 64a is disposed on the first anode lead portion 62a exposed on the bottom surface 70 of the recess 61a of the resin container 61, the second semiconductor light emitting element 64b is disposed on the second anode lead portion 62b, and the third The third semiconductor light emitting element 64c is bonded and fixed on the anode lead part 62c. Then, using a bonding wire, the p-type electrode of the first semiconductor light-emitting element 64a is connected to the first anode lead 62a, the p-type electrode of the second semiconductor light-emitting element 64b is connected to the second anode lead 62b, and the third The p-type electrode of the semiconductor light emitting device 64c is used as the third anode lead portion 62c, and the n-type electrodes of the first semiconductor light emitting device 64a, the second semiconductor light emitting device 64b, and the third semiconductor light emitting device 64c are used as the cathode lead portion 63, respectively. Connect to each.

Next, the concave portion 61a is filled with a mixed resin paste R containing phosphor powder 65a and uncured transparent resin 65b. At that time, the first semiconductor light emitting element 64a, is covered by the second semiconductor light emitting element 64b and the third semiconductor light emitting element 64c and the bonding wires mixed resin paste R, the liquid surface R ₁ of the mixed resin paste R upper surface of the resin vessel 61 It is recessed from 61b, and the amount d of the depression is set in the range of −20 μm to −100 μm from the upper surface 61b. For example, in the example shown in FIG. 4, the difference between the height of the end portion B ₁ of the height and the liquid surface R ₁ center A ₁ of the liquid surface R ₁ in the range of 20 m to 100 m.

  The filling of the mixed resin paste R into the concave portion 61a of the resin container 61 is preferably performed by a podding method using a paste discharge device. This discharge device includes a discharge nozzle N that discharges the mixed resin paste R and a control unit (not shown).

Mixed resin paste R is a true density in the range weight average particle diameter of 7μm or more 15μm or less with a 3 g / cm ³ or more 4.7 g / cm ³ or less of the range the phosphor powder 65a is, uncured state It is mixed with the transparent resin 65b, and the viscosity is adjusted to the range of 4000 cP to 15000 cP.

Here, the empty volume of the recess 61a in the state where the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c are attached is 6.5 μL, and the injection amount of the mixed resin paste R is repeated. For example, when the accuracy is ± 0.2 μL, when the injection amount varies by 0.2 μL, the height of the central portion A ₁ of the liquid surface R ₁ of the mixed resin paste R after injection varies by about 25 μm. Then, when the height of the liquid surface R ₁ moves, for example, 100 μm, the chromaticity y of the emission color of the light emitted from the emission surface 65c moves by 0.01. The movement becomes ± 0.0025.

The injection amount of the mixed resin paste R is controlled by the injection pressure. However, when the injection amount is moved by the minimum adjustment amount of the injection pressure, the injection amount varies by about 0.3 μL. This corresponds to moving the height of the liquid level R ₁ by 38 μm. When the control range of the chromaticity y of the luminescent color of the light emitting device 60 is set to ± 0.008, the injection pressure in a situation where the liquid level R ₁ after injection moves due to a change in the viscosity of the mixed resin paste R or the like. It is necessary to control the level of the liquid surface R ₁ to ± 40 μm by changing the injection amount by controlling. The height of the liquid level R ₁ can be measured with the above-described laser displacement meter (for example, ZSHLD2 manufactured by OMRON). At this time, to measure the distance to the liquid surface R ₁ after injection from connecting it midpoint ends B ₁ between the recess 61a. Before performing the curing heat treatment after injection, the height of the liquid level R ₁ is measured, and the injection pressure is controlled so that the position falls within the range of −20 μm to −100 μm from the midpoint connecting the end portions B _{1 of the} recess 61a. do it.

  Next, the mixed resin paste R is cured to form the sealing resin 65. The curing process may be performed by heating, for example. Thereafter, the lead frame is separated into the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63, and the lead frame is bent, so that the light emitting device 60 is obtained. Is obtained.

  Here, the dent amount d of the sealing resin 65 formed in the concave portion 61a of the resin container 61 of the light emitting device 60 and the true density and mass average particle diameter of the phosphor powder 65a constituting the sealing resin 65 are described above. The reason for limiting to the range will be described.

  When a plurality of the above-described light emitting devices 60 are used and used as a backlight of a liquid crystal display device, the chromaticity coordinates of the emitted colors by the respective light emitting devices 60 (for the purpose of suppressing the distribution of the chromaticity of the emitted color of the backlight as much as possible) The variation on x, y) is required to be within the range of ± 0.008. Further, when the light emitting device 60 continues to be lit for a long period of time, if the light emission color changes with time, the chromaticity of the light emission color varies during use, and this must be suppressed at the same time.

  The present inventor has found that the dispersion from the target chromaticity can be suppressed by uniformly dispersing the phosphor powder 65a in the transparent resin 65b in the sealing resin 65 of the light emitting device 60. It was. Factors that determine the white chromaticity of the light emitted from the light emitting device 60 include the concentration of the phosphor powder 65a in the sealing resin 65, the ratio of the green phosphor to the red phosphor, and the sealing resin that is formed. Three types of the shape of 65 emission surfaces 65c are considered. Therefore, the cause of the variation in the emission color of the light emitting device 60 is that the concentration of the phosphor powder 65a varies depending on the location in the sealing resin 65, or the ratio of the green phosphor and the red phosphor varies depending on the location. If the shape of the exit surface 65c of the sealing resin 65 formed in the recess 61a of the resin container 61 is changed, the chromaticity of the light emitted from the light emitting device 60 is changed, resulting in uneven color. . Further, in the manufacture of the light emitting device 60, as long as the phosphor powder 65a contained in the mixed resin paste R sinks to the bottom surface 70 side after the mixed resin paste R is injected into the recess 61a of the resin container 61, the sealing is performed. Variations in the concentration of the phosphor powder 65a in the stop resin 65 and variations in the ratio between the green phosphor and the red phosphor occur.

  Therefore, improving the uniform dispersibility of the phosphor powder 65a in the sealing resin 65 is important for stabilizing the chromaticity of light emitted from the light emitting device 60. In addition, when uniform dispersion of the phosphor powder 65a in the sealing resin 65 is achieved, the chromaticity varies greatly depending on the shape of the emission surface 65c of the sealing resin 65, so the shape of the emission surface 65c is managed. If the control is not performed together with the management of uniform dispersion, the dispersion of chromaticity may increase due to the uniform dispersion of the phosphor powder 65a. Furthermore, even if the phosphor powder 65 a is uniformly dispersed in the sealing resin 65, the output and chromaticity of the light emitted from the light emitting device 60 are the size, shape, and bottom surface 70 of the recess 61 a of the resin container 61. And the surface condition of the wall surface 80 is greatly affected. In contrast, the inventor of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63, which bears most of the bottom surface 70 of the recess 61a. It has been found that it is extremely important to give the silver plating layer a reflection characteristic close to Lambertian reflection in order to reduce light absorption and eliminate variations in emission color depending on the position in the exit surface 65c.

  If this is viewed from another point of view, the variation in emission color is independent of the mounting positions of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c on the bottom surface 70 of the recess 61a. It is possible to hold down. That is, the degree of freedom regarding the setting of the arrangement position of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c in the light emitting device 60 is increased.

  In the method for manufacturing the light emitting device 60 described above, if the phosphor powder 65a sinks before the transparent resin 65b is cured after the mixed resin paste R is injected into the recess 61a of the resin container 61, a plurality of In the light emitting device 60, it is substantially impossible to make the phosphor powder 65a sink in the same manner. Therefore, in order to cause the plurality of light emitting devices 60 to emit light with substantially the same chromaticity, the green phosphor and the red phosphor contained in the phosphor powder 65a are dispersed as uniformly as possible in the transparent resin 65b. It is desirable that

  In manufacturing the light emitting device 60, the mixed resin paste R, that is, the uncured transparent resin 65b containing the phosphor powder 65a can be stirred until it is potted into the concave portion 61a of the resin container 61. Generally, it takes about 1 hour to cure the uncured transparent resin 65b by heating. During this time, the phosphor powder 65a may settle in the recess 61a.

By the way, the sedimentation velocity Vs of the phosphor powder 65a in the uncured transparent resin 65b is in accordance with the Stokes equation represented by the following equation (1). In the formula (1), D _p is the mass average particle size of the phosphor powder 65a, [rho _p represents the true density of the phosphor powder 65a, the [rho _f is the density of the transparent resin 65b. g is the acceleration of gravity, and η is the viscosity of the uncured transparent resin 65b.

^{_{Vs = D p 2 (ρ p}} -ρ f) g / 18η ... (1)

  Here, in the mixed resin paste R potted in the recess 61a, the viscosity η of the transparent resin 65b before curing may be increased in order to reduce the sedimentation speed Vs so that the phosphor powder 65a is difficult to settle. However, if the viscosity η is too high, it becomes difficult to pot quantitatively.

Further, although the settling velocity Vs by reducing the mass average particle diameter D _p of the phosphor powder 65a decreases, when the too small weight average particle diameter D _p of the phosphor powder 65a, this time the phosphor powder 65a It becomes difficult to maintain the light emission characteristics.

Furthermore, if the true density ρ _p of the phosphor powder 65a is the same as the density of the transparent resin 65b, the phosphor powder 65a does not settle, but the true density of the uncured transparent resin 65b is 1.4 g / cm ^3. whereas a ~1.8g / cm ³ or so, most of the phosphor powder 65a the true density to containing heavy metals is much greater than 2.0 g / cm ^3.

As described above, one of the three characteristic values of the mass average particle diameter D _{p of} the phosphor powder 65a, the true density ρ _p of the phosphor powder 65a, and the viscosity η of the uncured transparent resin 65b is one. It is concluded that it is difficult to prevent sedimentation of the phosphor powder 65a by clearing only the above. That is, the transparent resin 65b having a large viscosity η is used as long as it can be quantitatively injected by potting, and the particle diameter is as small as possible within the range where the light emission characteristics can be maintained, and the true density as long as the light emission characteristics can be maintained It is necessary to select a phosphor powder 65a having a small size.

When the thickness of the sealing resin 65 of the light emitting device 60 shown in FIG. 3 is about 0.5 mm, when the phosphor powder 65a sinks 0.5 mm during one hour when the uncured transparent resin 65b is cured, Phosphor powder 65a settles on the bottom of the recess 61a. Therefore, in order to suppress variation in chromaticity, if it is attempted to suppress the sedimentation distance of the phosphor powder 65a within a negligible range, it is necessary to set the sedimentation distance in one hour to 0.05 mm or less. In order to enter this settling distance, the mass average particle diameter D _{p of} the phosphor powder 65a, the true density ρ _p of the phosphor powder 65a, and the viscosity η of the uncured transparent resin 65b are within the above ranges. It is necessary to put in.

  In addition, as one of the causes for causing the chromaticity variation of the emission color emitted from the light emitting device 60, there is an amount of the mixed resin paste R injected to form the sealing resin 65. In the case of a light emitting device 60 called a so-called top view package as shown in FIG. 3, the shape of the exit surface 65c of the obtained sealing resin 65 varies depending on the amount of the mixed resin paste R to be injected. More specifically, there are cases where the sealing resin 65 swells in a convex shape than the upper surface 61b of the resin container 61 and in a concave shape. When the mixed resin paste R injected into the recess 61a swells in a convex shape, the amount of the phosphor powder 65a that effectively works in wavelength conversion increases, and thus the same effect as when the concentration of the phosphor powder 65a is increased. As a result, the chromaticity of the emitted color shifts to increase both the x value and the y value. However, if the sealing resin 65 swells in a convex shape, it will be extremely difficult to handle because it will stick to each other when transported by a parts feeder or the like in the manufacturing process. Therefore, it is desirable to avoid the sealing resin 65 from becoming convex. For this reason as well, it can be said that it is preferable to align the sealing resin 65 into a concave shape with respect to the resin container 61. Further, even if the sealing resin 65 is drawn in a concave shape with respect to the resin container 61, the chromaticity of the output light emitted from the emission surface 65c varies depending on how much the sealing resin 65 is drawn. When the inventors measured the correlation, it was found that the Y value of chromaticity moved by 0.01 when the dent amount d moved by 100 μm. In the case of a backlight for a liquid crystal display device, the X value and the Y value are required to be within ± 0.008, respectively. Therefore, the dent amount d of the sealing resin 65 is set in a range of −20 μm to −100 μm. Must be stored.

From the above, in this embodiment, the true density [rho _p of the phosphor powder 65a contained in the sealing resin 65 with a 3 g / cm ³ or more 4.7 g / cm ³ or less in the range, the phosphor powder The mass average particle diameter D _p of the body 65a is in the range of 7 μm or more and 15 μm or less. Further, the recess amount d of the sealing resin 65 formed in the recess 61a of the resin container 61 is set in the range of −20 μm to −100 μm.

  As described above, according to such a light emitting device 60, the sealing resin 65 covering the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c has a true density within a predetermined range. And the phosphor powder 65a having a mass average particle diameter are mixed with the transparent resin 65b, so that the phosphor powder 65a can be uniformly dispersed in the transparent resin 65b. As a result, each light emitting device 60 can emit white light whose chromaticity y width is controlled within a range of ± 0.008.

  Further, the emission surface 65c of the sealing resin 65 is recessed from the upper surface 61b, and the amount d of the recess is set in the range of −20 μm to −100 μm from the upper surface 61b. The width of chromaticity y of white light can be kept within a range of ± 0.008.

  Moreover, according to the manufacturing method of the light-emitting device 60 described above, the phosphor powder 65a having the true density and the mass average particle size in the above range is mixed with the uncured transparent resin 65b to mix with a predetermined viscosity. Since the resin paste R is filled and cured so as to cover the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c, the sealing resin 65 is formed. The phosphor powder 65a can be uniformly dispersed therein. In addition, the exit surface 65c is recessed from the upper surface 61b, and the amount d of the recess is set in the range of −20 μm to −100 μm from the upper surface 61b, so that the white surface is uniform and less uneven in color from the exit surface 65c of the sealing resin 65. A light emitting device 60 from which light is emitted can be configured.

  In the light emitting device 60 of the present embodiment, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c are formed on the bottom surface 70 at the bottom surface 70 of the recess 61a by providing the above-described configuration. Even if it is arranged at a position different from the center C, it is possible to output white light that is uniform and has little color unevenness from the emission surface 65 c of the sealing resin 65.

<Embodiment 2>
FIG. 5 is a diagram for explaining a configuration of a light emitting device 60 to which the present exemplary embodiment is applied. Here, FIG. 5A shows a top view of the light emitting device 60, and FIG. 5B shows a VB-VB sectional view of FIG. 5A.

  The basic configuration of the light emitting device 60 is substantially the same as that used in the first embodiment. However, in the light emitting device 60, only the first semiconductor light emitting element 64a is mounted, and the second semiconductor light emitting element 64b and the third semiconductor light emitting element 64c are not mounted. Here, as in the first embodiment, the first semiconductor light emitting element 64a is attached to the first anode lead portion 62a exposed on the bottom surface 70, and the first anode lead portion 62a and the cathode lead portion 63 are attached. Is electrically connected.

  Further, in the light emitting device 60, the first semiconductor light emitting element 64a is disposed at a position shifted from the center C of the circular bottom 70 as in the first embodiment. Such a configuration is employed when it is difficult to dispose the first semiconductor light emitting element 64a at the center C of the bottom surface 70, for example, in order to perform the shape of the lead frame or wire bonding.

  As in the first embodiment, each surface of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63 has a glossiness of 0. Silver plating that falls within a range of 0.3 to 1.0, more preferably 0.5 to 0.7 is applied.

  Also in the light emitting device 60 of the present embodiment, the resin container 61 is made of a white resin with little light absorption, and the first anode lead part 62a, the second anode lead part 62b, and the third anode use part constituting the lead frame. A silver plating layer is formed on the surfaces of the lead part 62c and the cathode lead part 63, and the light absorption rate in the visible region is set to a range of more than 2% and less than 15%. Then, the gloss of silver plating formed on the surfaces of the first anode lead portion 62a, the second anode lead portion 62b, the third anode lead portion 62c, and the cathode lead portion 63 constituting the bottom surface 70 is reduced to 0. .3 and 1.0 and the wall surface 80 is made of a white resin to improve the light extraction efficiency, that is, the light emission efficiency, compared with the case of not having such a structure. Can do.

  Further, by providing the above-described configuration, even if the first semiconductor light emitting element 64a on the bottom surface 70 of the recess 61a is disposed at a position different from the center C of the bottom surface 70, the first semiconductor light emitting element 64a is homogeneous from the emission surface 65c of the sealing resin 65. White light with little color unevenness can be output.

  In the first and second embodiments, the example in which the light emitting module 12 configured using the light emitting device 60 is applied to the backlight device 10 of the liquid crystal display device has been described. However, the present invention is not limited thereto. is not. For example, by combining the light emitting module 12 with a shade or the like, the light emitting module 12 can be used as an illumination device that illuminates a space or an object.

  The light emitting device 60 described above can also be applied to, for example, a traffic light, a light source device for a scanner, an exposure device for a printer, an in-vehicle illumination device, an LED display device using an LED dot matrix, and the like.

  Furthermore, in the first embodiment, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c that output blue light, the phosphor that converts blue light into green light, and the blue light as red light Although the example which outputs white light using the fluorescent substance converted into light was demonstrated, it is not restricted to this. That is, the emission colors of the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c may be selected as appropriate, and the phosphor may be selected as appropriate.

Next, examples of the present invention will be described.
FIG. 6 is a diagram showing the relationship between each sample used in Examples and Comparative Examples and its configuration.
Here, the resin container 61 in which the vertical and horizontal sizes on the upper surface are set to 5.0 mm × 5.5 mm is used. Here, the light absorption rate of the white resin constituting the resin container 61 is 7%. The light emitting device 60 used has the structure shown in FIG. 3, and each of the three semiconductor light emitting elements, that is, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c. It is installed.

  Here, seven types of lead frames having silver plating with different glossiness are combined with the resin container 61 described above. The glossiness of the silver plating layer corresponds to the formation of the lead frame surface irregularities. Here, the light emitting device 60 having a lead frame with a glossiness of 0.1 is referred to as a sample S1. A light emitting device 60 having a lead frame with a glossiness of 0.3 is referred to as sample S2. Furthermore, the light-emitting device 60 having a lead frame with a glossiness of 0.5 is referred to as sample S3. Furthermore, the light emitting device 60 having a lead frame with a glossiness of 0.6 is referred to as sample S4. The light emitting device 60 having a lead frame with a glossiness of 0.7 is referred to as sample S5. Further, the light emitting device 60 having a lead frame with a glossiness of 1.0 is referred to as sample S6. And the light-emitting device 60 which has a lead frame whose glossiness is 1.3 is called sample S7. In this example, samples S2 to S6 are examples of the present invention, and samples S1 and S7 are comparative examples of the present invention.

  Here, in the sample S1, the silver plating layer of the lead frame is in a so-called matte white state with no gloss, and exhibits characteristics very close to Lambertian reflection. In Samples S2 to S6, the silver plating layer of the lead frame is in a semi-glossy state and shows partial Lambertian reflection characteristics. On the other hand, in the sample S7, the silver plating layer of the lead frame is in a so-called all-gloss state with a very high gloss, and exhibits characteristics very close to perfect specular reflection.

Then, the preparation procedure of each sample S1-S7 is demonstrated easily.
Samples S1 to S7 having the above-described shape of the resin container 61 were prepared by forming 40 resin containers 61 with white resin for one lead frame. In each of the samples S1 to S7, the depth of the recess 61a of the resin container 61 is all 0.6 mm.

  Then, the first semiconductor light emitting element 64a, the second semiconductor light emitting element 64b, and the third semiconductor light emitting element 64c are die-bonded to each resin container 61 using a die attach paste and heated at 150 ° C. for 2 hours. After the die attach paste was cured, wire bonding was performed using 4N gold wires made of Tanaka Kikinzoku with a diameter of 25 μm.

Further, an uncured transparent resin 65b made of a silicon resin having a viscosity of 9000 cP and a density of 1.7 g / cm ³ at the time of injection, an excitation wavelength of 450 nm at a density of 4.5 g / cm ³ and a mass average particle diameter at an emission wavelength of 530 nm. A mixed resin paste R in which a phosphor powder 65a containing a 12 μm silicate phosphor and a nitride phosphor having a density of 4.2 g / cm ³ with an excitation wavelength of 460 nm and an emission wavelength of 640 nm and a mass average particle diameter of 9 μm is kneaded. Got ready. Here, the mixing amount of the phosphor powder 65a with respect to the transparent resin 65b is fixed at 5.8 mass% for the green phosphor and 2.1 mass% for the red phosphor.

  Then, 6.8 μL each of the mixed resin paste R obtained in this manner was injected into the recess 61a of the resin container 61 using the discharge nozzle N of the automatic resin injector. In this example, as described above, 40 resin containers 61 are provided in one lead frame. Therefore, 400 lead frames were prepared, and a total of 16000 light-emitting devices 60 were made as a prototype. Note that it took about 1.5 seconds to inject the mixed resin paste R into one resin container 61.

About each obtained sample S1-S7 (light-emitting device 60), the shape of the upper surface of the output surface 65c was measured with the laser displacement meter mentioned above. Before starting, a dummy was poured, and the injection amount was finely adjusted so that the average value (average dent amount) of the ten dent amounts d was −60 μm ± 10 μm. When the average dent amount of one lead frame was shifted by 20 μm or more, the injection pressure was changed and adjusted to fall within −60 μm ± 10 μm. The variation within one lead frame was σ = about 11 μm.
Here, the smaller the injection amount of the mixed resin paste R, the larger the variation. However, when averaged with one lead frame, the movement of the dent amount d moved almost the same with time. As a result, no matter which resin container 61 was used, the dent amount d could be set to -20 μm to −100 μm. After the injection of the mixed resin paste R, heat was applied at 150 ° C. for 4 hours to perform a curing process.

  For each of the obtained light emitting devices 60, the output P (mW), total luminous flux Φ (lm), luminous efficiency E (lm / W), and chromaticity (x, y) are obtained using an integrating sphere manufactured by Labsphere. Measurements were made. At this time, the energization current I was 20 mA. These measurement results were average values of the 20 light emitting devices 60 constituting each of the samples S1 to S7. The chromaticity (x, y) is represented by an x value and a y value in the CIE Yxy (XYZ) color system.

  Moreover, the orientation dependence (chromaticity dispersion | variation) of the chromaticity of the light output from each sample S1-S7 was measured using the spectral radiance meter (Konica Minolta CS1000S). This measurement was performed according to the following procedure. With respect to the direction perpendicular to the light emitting surface (light emitting surface 65c) of the light emitting device 60, it is assumed that a vertical line is set up at the center of the light emitting surface, and 0 to 180 degrees with respect to the vertical line in one plane including this vertical line. Measurements were made in the range. On the other hand, the direction parallel to the light emitting surface was measured by rotating 360 ° within the plane parallel to the light emitting surface when tilted 60 ° from the perpendicular. The degree of chromaticity variation is indicated by the maximum and minimum differences between the x value and the y value, ie, xΔmax-min and yΔmax-min, in the direction perpendicular to and parallel to the exit surface 65c. Further, in each of the samples S1 to S7, 1000 light emitting devices 60 were measured from the front of the emission surface 65c, and chromaticity variation, which is a standard deviation between x and y, was evaluated. Here, the former aims to quantify the change in chromaticity depending on the orientation in a single light emitting device 60, and the latter quantifies variations in chromaticity in a plurality of light emitting devices 60. It is intended to do.

  FIG. 7 is a diagram showing the relationship between each sample used in Examples and Comparative Examples and the obtained characteristics. More specifically, FIG. 7 shows from the samples S1 to S7, the energization current I (mA) for each sample S1 to S7, the applied voltage V (V) for each sample S1 to S7, and the samples S1 to S7. Light output P (mW), total luminous flux Φ (lm) output from each sample S1 to S7, luminous efficiency E (lm / W) of each sample S1 to S7, chromaticity of emission color of each sample S1 to S7 (X, y), variation σ of chromaticity y of each sample S1 to S7, xΔmax-min and yΔmax-min corresponding to variation in chromaticity in the vertical direction of each sample S1 to S7, and each sample S1 to S7 The relationship between xΔmax-min and yΔmax-min corresponding to the degree of chromaticity variation in the parallel direction is shown.

FIG. 8 is a graph showing the relationship between the glossiness of each of the samples S1 to S7 and the light emission efficiency E based on the relationships shown in FIGS.
As can be seen from FIG. 8, the gloss of the lead frame becomes semi-gloss as compared to the gloss level of 0.1 where the lead frame is almost non-gloss = 0.1 and the gloss level of 1.3 where the lead frame is almost specular. It can be seen that higher luminous efficiency E is obtained in the range of degree = 0.3 to 1.0. It can also be seen that higher luminous efficiency E can be obtained particularly in the glossiness range of 0.5 to 0.7. This is because, for example, when the glossiness of the lead frame is 0.1, the light absorption rate of the lead frame at that time has increased to 12%, so that the influence of light absorption by the lead frame increases. is there. On the other hand, for example, when the glossiness of the lead frame is 1.3, since the reflection characteristics of the lead frame are close to mirror reflection, the number of reflections until the light reflected by the lead frame escapes from the exit surface 65c increases. This is because the influence of light absorption by the lead frame and the white resin is increased. Therefore, it is understood that the glossiness of the lead frame may be selected from the range of 0.3 to 1.0, more preferably from the range of 0.5 to 0.7.

  FIG. 9 shows the glossiness of each of the samples S1 to S7 and the maximum and minimum differences xΔmax-min and yΔmax between the x value and the y value in the direction perpendicular to the exit surface 65c, from the relationship shown in FIGS. It is a graph which shows the relationship with -min. In FIG. 9, for example, the maximum / minimum difference xΔmax-min of the x value is shown as (x), and the maximum / minimum difference yΔmax-min of the y value is shown as (y).

  As can be seen from FIG. 9, on the emission surface 65 c of each light emitting device 60 in the range of glossiness = 0.1 to 1.0, compared to glossiness = 1.3 where the lead frame is almost specular. It can be seen that variations in the x-value and y-value in the vertical direction are reduced, in other words, color unevenness of light emitted from each light-emitting device 60 is suppressed.

  On the other hand, FIG. 10 shows the relationship between the glossiness of each of the samples S1 to S7 and the maximum and minimum differences xΔmax-min and yΔmax between the x value and the y value in the direction parallel to the exit surface 65c. It is a graph which shows the relationship with -min. In FIG. 10, as in FIG. 9, for example, the maximum / minimum difference xΔmax-min of the x value is shown as (x), and the maximum / minimum difference yΔmax-min of the y value is shown as (y).

  As can be seen from FIG. 10, on the exit surface 65c of each light emitting device 60 in the range of glossiness = 0.1 to 1.0, compared to glossiness = 1.3 where the lead frame is almost specular. It can be seen that variations in the x-value and y-value in the parallel direction are reduced, in other words, uneven color of the light emitted from each light-emitting device 60 is suppressed. However, as shown in FIG. 8, when the glossiness = 0.1 at which the lead frame becomes almost matte, the glossiness at which the leadframe becomes semi-gloss = 0.3-1.0. , The luminous efficiency E is lowered. Therefore, it is understood that the glossiness of the lead frame may be selected from the range of 0.3 to 1.0, more preferably from the range of 0.5 to 0.7.

  Further, FIG. 11 is a graph showing the relationship between the glossiness of each of the samples S1 to S7 and the variation in chromaticity y between the light emitting devices 60 based on the relationships shown in FIGS. Here, 20 samples S1 to S7 are prepared, and the variation in chromaticity y of light output from each of the 20 light emitting devices 60 constituting each sample S1 to S7 is evaluated by σ. ing.

  As is apparent from FIG. 11, the variation σ of the chromaticity y is smaller in the range of glossiness = 0.1 to 1.0 compared to the glossiness = 1.3 where the lead frame is almost specular. In other words, it can be seen that uneven color between the light emitting devices 60 is suppressed. However, as shown in FIG. 8, when the glossiness is 0.1 when the lead frame is almost matte, the glossiness when the leadframe is semi-gloss is 0.3 to 1.0. However, the luminous efficiency E is lowered. Therefore, it is understood that the glossiness of the lead frame may be selected from the range of 0.3 to 1.0, more preferably from the range of 0.5 to 0.7.

It is a figure which shows the whole structure of a liquid crystal display device. It is a figure for demonstrating the structure of a backlight apparatus. 3 is a diagram for illustrating a configuration of a light-emitting device according to Embodiment 1. FIG. It is a figure for demonstrating the manufacturing method of a light-emitting device. 6 is a diagram for illustrating a configuration of a light-emitting device according to Embodiment 2. FIG. It is a figure which shows the relationship between each sample used by the Example and the comparative example, and its structure. It is a figure which shows the relationship between each sample used by the Example and the comparative example, and the acquired characteristic. It is a graph which shows the relationship between the glossiness of each sample, and luminous efficiency. It is a graph which shows the relationship between the glossiness of each sample, and the maximum and minimum difference of x value in a direction perpendicular | vertical to an output surface, and y value. It is a graph which shows the relationship between the glossiness of each sample, and the maximum and minimum difference of x value in a direction parallel to an output surface, and y value. It is a graph which shows the relationship between the glossiness of each sample, and the dispersion | variation in chromaticity y between light-emitting devices.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Backlight apparatus, 12 ... Light emission module, 50 ... Liquid crystal display module, 51 ... Liquid crystal panel, 60 ... Light emission apparatus, 61 ... Resin container, 61a ... Recessed part, 61b ... Upper surface, 62a ... Lead part for 1st anode, 62b ... 2nd anode lead part, 62c ... 3rd anode lead part, 63 ... Cathode lead part, 64a ... 1st semiconductor light emitting element, 64b ... 2nd semiconductor light emitting element, 64c ... 3rd semiconductor light emitting element, 65 ... Sealing resin, 65a ... phosphor powder, 65b ... transparent resin, 65c ... outgoing surface, 70 ... bottom surface, 80 ... wall surface

Claims (17)

A resin container having a recess including a bottom surface and a wall surface rising from the periphery of the bottom surface;
It has a metal conductor and a silver plating layer having a glossiness of 0.3 or more and 1.0 or less formed on the surface of the metal conductor, and is arranged in a state exposed on the bottom surface of the recess of the resin container A conductor portion to be
A light emitting element attached to a position different from a center position of the bottom surface on the bottom surface of the concave portion and electrically connected to the conductor portion;
A transparent resin transparent to the light emission wavelength of the light emitting element, and a phosphor dispersed in the transparent resin and converting the light emission wavelength of the light emitting element into light having a longer wavelength, and sealing the light emitting element in the recess. A light emitting device including a sealing resin to be stopped.   2. The conductor portion reflects light from the light emitting element according to a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. The light emitting device described.   3. The light emitting device according to claim 1, wherein the resin container is whitened using a white pigment.   The light emitting device according to any one of claims 1 to 3, wherein the silver plating layer in the conductor portion has a glossiness of 0.5 or more and 0.7 or less. The light emitting element outputs blue light,
The phosphor includes a first phosphor that converts the blue light into green light and outputs the light, and a second phosphor that converts the blue light into red light and outputs the light. Item 5. The light emitting device according to any one of Items 1 to 4.   The light-emitting device according to claim 1, wherein the transparent resin is made of silicon resin. The sealing resin has an emission surface for emitting the light output from the light emitting element to the outside,
The exit surface has a concave shape that is recessed from the boundary side with the resin container toward the center side, and the amount of recess of the exit surface is set in a range of 20 μm or more and 100 μm or less. The light-emitting device according to claim 1. A resin container having a recess;
It has a metal conductor and a silver plating layer having a glossiness of 0.3 or more and 1.0 or less formed on the surface of the metal conductor, and is formed in a state of being exposed inside the recess of the resin container. A conductor portion;
A plurality of light emitting elements provided inside the recess and electrically connected to the conductor portion;
A transparent resin transparent to the emission wavelength of the plurality of light emitting elements, and a phosphor that is dispersed in the transparent resin and converts the emission wavelength of the light emitting element into light having a longer wavelength. A light emitting device including a sealing resin for sealing the light emitting element.   9. The conductor portion reflects light from the light emitting element according to a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. The light-emitting device of description.   The light emitting device according to claim 8, wherein the resin container is made of a resin containing titania fine particles.   11. The light emitting device according to claim 8, wherein the silver plating layer in the conductor portion has a glossiness of 0.5 or more and 0.7 or less.   The light emitting device according to any one of claims 8 to 11, wherein a light reflectance of the resin container and the silver plating layer of the conductor portion in a visible region is 85% or more and 98% or less.   The light emitting device according to any one of claims 8 to 12, wherein an area of the conductor portion exposed on a bottom surface of the recess is set to be half or more of a total area of the bottom surface. A substrate,
A plurality of light emitting devices attached to the substrate;
The light emitting device
A resin container having a recess including a bottom surface and a wall surface rising from the periphery of the bottom surface;
It has a metal conductor and a silver plating layer having a glossiness of 0.3 or more and 1.0 or less formed on the surface of the metal conductor, and is arranged in a state exposed on the bottom surface of the recess of the resin container A conductor portion to be
A light emitting element attached to a position different from a center position of the bottom surface on the bottom surface of the concave portion and electrically connected to the conductor portion;
A transparent resin transparent to the light emission wavelength of the light emitting element, and a phosphor dispersed in the transparent resin and converting the light emission wavelength of the light emitting element into light having a longer wavelength, and sealing the light emitting element in the recess. A light emitting module comprising: a sealing resin that stops.   The conductor portion of the light emitting device reflects light from the light emitting element by a Lambertian reflection characteristic obtained by a silver plating layer having a glossiness of 0.3 or more and 1.0 or less. The light emitting module according to claim 14.   The light emitting module according to claim 14 or 15, wherein the resin container of the light emitting device is whitened using a white pigment.   The light emitting module according to any one of claims 14 to 16, wherein the silver plating layer in the conductor portion of the light emitting device has a glossiness of 0.5 or more and 0.7 or less.

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